1. Field of the Invention
This invention relates to the manufacture of sucker rods for use in the oil industry, and in particular, it relates to a novel apparatus and method which are useful when such sucker rods are being manufactured with the use of an induction normalizing heat-treating step of the kind disclosed in my co-pending application Ser. No. 306,885, filed Sept. 30, 1981, now abandoned.
2. Description of the Prior Art
The general outline of the process of making sucker rods for use in the oil industry is familiar to those skilled in the art. Rod stock received from the steel manufacturer is straightened, the ends of the rods are heated to a forging temperature, the ends are forged to produce the usual features required at the ends of a sucker rod (such as the elevator button, the wrench square, and the pins), the forged rods are heat-treated, and the threads are rolled onto the pins. In the above-mentioned heat-treating step, the steel is sometimes heated to an austenitizing temperature, quenched and tempered; in some other instances, the treatment is normalizing, i.e., heating to approximately 1650.degree. F., followed by cooling in still air. In any event, in accordance with the methods used before the invention of the above-mentioned pending patent application Ser. No. 306,885, the heat treatment was done with the use of a gas-fired furnace. The above-mentioned patent application teaches normalizing with the use of an induction furnace operating at a frequency of 7500 to 10,000 hertz.
Those skilled in the art of making sucker rods have not, as indicated above, ordinarily been required to confront the problems which attend the operation of receiving and permitting to cool in air the hot rods emerging from the electric induction furnace which is employed in connection with the method of the above-mentioned co-pending application.
One of the problems, in such an operation, is that the rods tend to warp during their cooling unless they are nearly continuously kept turning. Another problem is that it is necessary to keep the rods supported so that they will remain straight. It is desirable to have equipment so that this may be done with a minimum of labor.